need some help again,put 350 ci. 290 hp crate engine in ,pulled 305 ci out all new parts from fuel pump to distributor ,idles rough, removed intake and carb replaced with edlebrock intake and carb (600) put distributor in at o degrees tdc ,rotor at 4 oclock and have wired no.1 from there,fuel pump pressure and volume its okay,set timing at 10 degrees idle shaky set it at20 runs better no backfire, slight hesitation in throttle then it revs up,vacuum is
16 when timing at 10, vac is 18 when timing at 20 ,but vac goes from 18 to19 to18 then 17 back to18 slowly not rapidly,no black smoke,has a catylatic converter (new) i dont know if i have too much back pressure,compression test was 125 psi all the way around. what have i missed ?
thanks soup